Water heater with flammable vapor and co sensors

ABSTRACT

A water heater including a water container, a combustion chamber adjacent the water container, a burner associated with the combustion chamber, a flue gas collector located to receive flue gases generated in the combustion chamber, a CO sensor having at least an operative portion proximate the flue gas collector, a flammable vapor sensor having at least an operative portion positioned proximate a location where combustion air enters the combustion chamber, and a controller operatively connected to the CO and flammable vapor sensors and adapted to receive signals generated by the CO and flammable vapor sensors and responsively shut off combustion in the combustion chamber.

RELATED APPLICATION

This patent application claims the benefit of U.S. ProvisionalApplication No. 60/784,144, filed Mar. 20, 2006. This earlierprovisional application is hereby incorporated by reference.

TECHNICAL FIELD

The technology in this disclosure relates to water heaters, particularlyto water heaters that have a flammable vapor sensor and a CO sensor.

BACKGROUND

A number of water heaters have been developed that are flammable vaporignition resistant (FVIR). Such water heaters are sold and available onthe market today. However, under certain circumstances with certaintypes of FVIR water heaters, lint, dirt or other particles may collectover the course of time, thereby reducing the amount of combustion airavailable to the water heater. This has the potential of causing anumber of disadvantages, including possible production of more thanoptimal amounts of CO. This is a result of incomplete combustion that isbrought about by the insufficiency of combustion air. Insufficientcombustion air may also occur in view of insufficient openings into theenclosed space in which the water heater is located, incorrect venting,other air-consuming appliances located within close proximity, vacuumconditions in the area near the water heater due to the tightness of thestructure in which the water heater is located and the like.

Some attempted solutions to those problems include utilizing temperaturesensors or switches in and around the combustion chamber to indirectlydetermine incomplete combustion.

SUMMARY

I provide a water heater including a water container, a combustionchamber adjacent the water container, a burner associated with thecombustion chamber, a flue gas collector located to receive flue gasesgenerated in the combustion chamber, a CO sensor having at least anoperative portion proximate the flue gas collector, a flammable vaporsensor having at least an operative portion positioned proximate alocation where combustion air enters the combustion chamber, and acontroller operatively connected to the CO and flammable vapor sensorsand adapted to receive signals generated by the CO and flammable vaporsensors and responsively shut off combustion in the combustion chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a water heater, partially taken insection.

FIG. 2 is a schematic of a gas control valve and selected connectedwater heater components associated with the water heater of FIG. 1.

FIG. 3 is a partial sectional view of another water heater, partiallytaken in section.

FIG. 4 is a schematic of a gas control valve and selected connectedwater heater components associated with the water heater of FIG. 3.

DETAILED DESCRIPTION

It will be appreciated that the following description is intended torefer to specific aspects of the structure selected for illustration inthe drawings and is not intended to define or limit this disclosure,other than in the appended claims.

Water heaters described herein can assist in reducing the likelihoodthat flammable vapors outside a water heater will be ignited by thewater heater itself. This may be achieved with a CO sensor having anoperative portion proximate to the water heater draft hood and aflammable vapor sensor having at least its operative portion positionedproximate the location where combustion air enters the combustionchamber. Both the CO sensor and flammable vapor sensor are connected toa controller which receives information generated by the CO andflammable vapor sensors and responsively shuts off combustion in thecombustion chamber, depending on the received information.

Turning now to the drawings generally and FIGS. 1 and 2 in particular, awater heater 10 including a water tank/container 12 having a water inlet14 and a water outlet 16 is shown. A flue 18 extends upwardly throughthe tank and outwardly from the top of water heater 10. Tank 12 issurrounded by insulation 20 and a jacket 21. Such insulation may be madefrom any number of foam type insulations well known in the art and/orfiberglass insulation such as around the lower portion of the waterheater. Various substitutions may be made without varying from thefundamental spirit of the disclosure.

A combustion chamber 22 is located below tank 12 and formed by tankbottom 24, skirt 26 and bottom pan 28. Bottom pan 28 sits on legs 30. Aburner 32 formed from a plenum 68 is positioned in combustion chamber22. Burner 32 is also positioned to receive fuel from fuel line 34,which connects to gas control valve 36, which connects to a fuel supplyline 38 connected to a fuel supply that is not shown.

Burner 32 is positioned within combustion chamber 22 and is a so-called“low NO_(x)” burner in this instance. It is, however, possible toutilize other types of burners that combust gas (either natural gas,propane or the like) or oil or other fuel. Many other types of burnersare known and need not be discussed herein.

Fuel line 34 connects to and extends through door 44 such that the endof fuel line 34, which is nozzle 46, is proximate open end 58 of aventuri 50. Fuel exits nozzle 46 and flows directly into the exteriorend. Although FIG. 1 shows a venturi 50, any number of fuel/air supplylines may be utilized such as tubes, pipes, pathways, conduits and otherstructures capable of channeling fuel and/or air to burner 32. Burner 32may be held above pan 28 by support 53. Pilot fuel line 35 extendsbetween gas valve 36 and pilot burner 86 (partially shown in FIG. 1).

A cover 45 also connects to door 44 and in this case serves severalpurposes. Cover 45 holds fuel line 34 in a desired position with respectto the open end 58 of venturi 50 so that fuel is directed in a desiredlocation through open end 58 and within venturi 50. Cover 45 providesthe desired nozzle to venturi alignment. Other structures may be used asalternatives. The top of cover 45 may be solid to prevent dust and otherairborne particulate from entering burner 32. The sides and bottom maybe perforated, enclosed in screen, or louvered to prevent rodents andlarge insets from entering and clogging venturi 50. Also,interchangeable nozzles 46 can be mounted in the front part of cover 45.

In operation, burner 32 operates under the fundamental condition thatfuel is supplied to venturi 50 and combustion air is mixed at the end 58of venturi 50 and the mixed fuel flows into plenum 68 and may further bemixed and distributed by some type of diffuser as desired. The air andfuel mixture is then combusted along the surface of a screen 33 locatedon top of plenum 68 in the usual manner.

FIGS. 1 and 2 show a pilot burner 86 connected to pilot fuel supply 35.Pilot burner 86 is mounted on a pilot mounting bracket (not shown) nearscreen 33 of burner 32. A power plug 31 connects to gas control valve 36to supply power from, for example, a typical household electricaloutlet. A transformer (not shown) can also be used to convert powersupplied from outside to an appropriate power type/level for gas controlvalve 36 and/or other remotely located controllers.

Gas control valve 36 also connects to a flammable vapor sensor 80 by wayof connection line 82. Flammable vapor sensor 80 is positioned in thevicinity of or proximate to the location where combustion air enterscombustion chamber 22. Although this location is shown proximate cover45 and door 44 of water heater 10 in FIG. 1, the location of entry ofcombustion air into combustion chamber 22 may be altered in accordancewith selected design features and burners utilized. In the case that anadditional passageway is provided to supply combustion air to combustionchamber 22, such as a conduit having an opening at an upper portion ofthe water heater, the flammable vapor sensor 80 may be located outsidethe opening (albeit near the upper portion of the water heater), justinside the opening, anywhere along the conduit or just outside of thecombustion chamber and still be considered in the vicinity of or“proximate a location where combustion air enters the combustionchamber.”

Also, combustion chamber 22 may have more than one opening. For example,an opening covered by a flame trap/flame arrestor (not shown) such as anair inlet/flame trap of the type as disclosed in any of U.S. Pat. Nos.5,797,355; 6,142,106; 6,085,699 and the like may be used. In such cases,more than one flammable vapor sensor may be used.

Thus, the position of sensor(s) 80 is not particularly limited so longas it is sufficiently close to the opening(s) in the combustion chamber22 through which combustion air is drawn to be effective in accuratelymeasuring/sensing flammable vapors. A number of flammable vapor sensorsare known and may be used in accordance with water heaters disclosedherein. One particular example is manufactured by Therm-O-Disc ofMansfield, Ohio.

A CO detector 94 also connects to gas control valve 36 by way of aconnection line 96. CO sensor 94 may be any type of known CO sensor. Oneexample is a CO sensor manufactured by Applied Sensor, Inc. CO sensor 94in FIG. 1 is located proximate the location where flue gases exit flue18 and proceed into draft hood 88. In this particular instance, COsensor 94 is located exteriorly of draft hood 88 with at least a portionextending interiorly of draft hood 88 to be in contact with flue gasesexiting the flue 18. Other locations may be employed so long as COsensor 84 is located to effectively detect/sense a selected amount of COexiting from flue 18.

Sensors 80 and 94 have been shown as connected to gas control valve 36by way of connection lines 82 and 96, respectively, which are typicallywire connections. However, this is merely one example of a means foroperatively connecting those sensors to gas control valve 36. Othermeans may be used such as optical fiber or wireless transmission, forexample. Gas control valve 36 may also connect to thermister 90 by wayof connection line 92. Thermister 90 senses the temperature within watertank 12 and transmits temperature information to gas control valve 36.

Referring to FIGS. 3 and 4, an alternate water heater 10 is shown. Waterheater 10 in FIG. 3 contains a different type of burner 32 than theburner of FIG. 1. It, too, is a conventional well known burner and itsfundamental operation need not be discussed further herein. Water heater10 of FIG. 3 also includes a pilot burner 86 that connects to gascontrol valve 36 by way of pilot fuel supply line 35. Thermopile 84connects to gas control valve 36 by way of connection line 85.

The gas control valve 36 shown in FIG. 4 generates power by means ofthermopile 84. Pilot burner 86 supplies heat to thermopile 84, whichgenerates an electrical current such as about 100-about 750 millivolts.This amount of power is sufficient to enable gas control valve 36 toperform all of its designated tasks. Also, this arrangement can produceenough power to supply any controller located in a position remote fromgas control valve 36.

In operation, both water heaters 10 of FIGS. 1 and 3 draw combustion airinto combustion chamber 22 through selected openings. In so doing,combustion air is drawn past flammable vapor sensor 80. In the unlikelyevent that flammable vapors are present at a concentration or in anamount selected by the manufacturer to detect such flammable vapors,sensor 80 sends corresponding information/a signal to gas control valve36. In response, gas control valve 36 can typically shut off the supplyof fuel 32 (and pilot burner 86 when present) to assist in avoidingignition of flammable vapors outside of water heater 10.

Similarly, CO sensor 94, located proximate draft hood 88, can sense thepresence of a selected quantity of CO that is indicative of incompletecombustion associated with water heater 10 for any reason. Thus, COsensor 94 generates information/a signal that is transmitted to gascontrol valve 36. In response, gas control valve 36 can typically shutoff the supply of fuel to burner 32 (and pilot burner 86 when present)to assist in avoiding ignition of flammable vapors outside of waterheater 10.

Gas control valve 36 can include a microcontroller that is capable ofcollecting the sensor information and taking appropriate action,including shutting off fuel or engaging other water heater components(not shown) to shut off the air supply to combustion chamber 22 or othertypes of components, for example. The microcontroller may be integralwith gas control valve 36 or located at an alternative location so longas it is operatively connected to gas control valve 36. Themicrocontroller can be programmable if desired.

Although this disclosure has been described selected, with specificforms of a water heater and associated components, it will beappreciated that a wide variety of equivalents may be substituted forthe specified elements described herein without departing from thespirit and scope of this disclosure as described in the appended claims.

1. A water heater comprising: a water container; a combustion chamberadjacent the water container; a burner associated with the combustionchamber; a flue gas collector located to receive flue gases generated inthe combustion chamber; a CO sensor having at least an operative portionproximate the flue gas collector; a flammable vapor sensor having atleast an operative portion positioned proximate a location wherecombustion air enters the combustion chamber; and a controlleroperatively connected to the CO sensor and the flammable vapor sensorand adapted to receive signals generated by the CO and flammable vaporsensors and responsively shut off combustion in the combustion chamber.2. The water heater of claim 1, wherein the flue gas collector is adraft hood.
 3. The water heater of claim 1, wherein the CO sensor isinside the flue gas collector.
 4. The water heater of claim 1, whereinthe controller is a gas control valve.
 5. The water heater of claim 4,wherein the gas control valve contains a microcontroller.
 6. The waterheater of claim 5, wherein the microcontroller is programmable.
 7. Thewater heater of claim 5, wherein the microcontroller is powered by agrid electrical supply.
 8. The water heater of claim 5, wherein themicrocontroller is powered by a thermopile.
 9. The water heater of claim8, wherein the thermopile receives heat from a pilot burner.
 10. Thewater heater of claim 1, wherein the controller is located proximate towhere the combustion air enters the combustion chamber.
 11. The waterheater of claim 1, wherein the flammable vapor sensor is located on thecontroller.
 12. The water heater of claim 1, wherein the controllershuts off fuel to the burner.